4) Lens Sharpness, Contrast and Color Rendition
The Nikon 24-85mm VR produces images with great contrast and colors, as can be seen from some of the sample images in this review. It does not have the “magic” of Nano coated glass though, so it is not quite as good as some of Nikon’s pro-level zooms in my opinion, especially when dealing with bright sources of light. Sharpness-wise, it is quite good, but definitely not in the same league as Nikon’s excellent zoom lenses like Nikon 24-120mm VR.
Take a look at the following sharpness charts that illustrate the optical performance of the lens at different focal lengths from 24mm to 85mm:
At 24mm, the lens has fairly good center and mid-frame sharpness, but definitely does suffer in the corners.
It gets a little better at 35mm with increased resolution throughout the aperture range, but still rather weak in the corners overall. Noticeable field curvature yields to increased center sharpness at the expense of corner performance.
The corners improve more at 50mm mark, but the mid-frame takes a slight hit at maximum aperture.
70mm seems to be the best focal length for the corners.
By 85mm, the overall performance from center to corner is somewhat normalized. The best overall performance at all focal lengths seems to be around the f/11 mark, which is quite normal for this type of a lens.
5) Vibration Reduction – VR II
I am a big fan of Vibration Reduction (VR) lenses – I wish every lens had VR in it, because it is one of the most useful lens features for low-light photography. VR certainly does work very well on zoom lenses and the Nikon 24-85mm VR comes with the latest version of Vibration Reduction called “VR II”, which is supposed to deliver sharp images up to four stops the shutter speed.
If you have used lenses like the Nikon 24-70mm in the past for hand-held, low-light work and try the 24-85mm, you will suddenly realize how useful VR would be on the 24-70mm. When Nikon released the 16-35mm lens (which was the first image-stabilized short-focal zoom lens in the world) so many photographers at first stated that VR for such short focal lengths would be useless. Those who tried out the 16-35mm quickly discovered that VR actually works great even for short focal lenses. I am glad that Nikon added VR to the Nikon 24-85mm lens – it certainly needs it.
Here is a shot that I captured hand-held at 1/6th of a second at 24mm with VR turned on:
6) Focus Shift and Field Curvature
During my lab testing, I did not see any major focus shift issues with the Nikon 24-85mm f/3.5-4.5G VR lens. As for field curvature, the lens does exhibit quite a bit of field curvature, which is something we can see on other similar-grade lenses as well.
As I have shown in my Nikon 28mm f/1.8G review, field curvature can be quite painful, yielding inconsistent performance from the center of the frame to the corners. Coupled with focus shift, it can cause some frustration and one has to fully understand these limitations when working in the field.
Variable aperture zoom lenses are generally quite weak in rendering good-looking backgrounds, also known as “bokeh” (see What is Bokeh?). Although bokeh on the 24-85mm does not appear as harsh as in some lenses, the small maximum aperture is the limiting factor for good subject isolation, which is again expected from this type of a lens. Take a look at the below image sample that shows the quality of background blur:
And a 100% crop from the above image:
As expected, the Nikon 24-85mm shows pronounced vignetting at various focal lengths. At 24mm, the amount of vignetting is very high in the corners, reaching up to 4 EVs at maximum aperture. Vignetting goes down significantly when the lens is stopped down to f/5.6 and smaller, but still stays rather high at this focal length. As the focal length is increased, vignetting normalizes quite a bit, with longest focal lengths showing the least amount of light falloff. Take a look at lens vignetting at different apertures (the below numbers are computed as a mean value from all four corners of the frame):
And here is a a graph that shows the spread of light falloff across the image frame at 24mm, f/3.5 (worst vignetting levels):
9) Ghosting and Flare
Ghosting and flare are both handled well, definitely better than older lenses with limited or no coating, but not quite as good as some of the Nano-coated Nikkor lenses. Adding low-quality glass filters (or shooting through a glass window) can add more to ghosting and flare, as shown in the below image:
Depending on the location of the bright source, these optical issues can be practically eliminated, especially without any filters in place:
The Nikon 24-85mm VR exhibits a lot of pronounced distortion at all focal lengths. At the shortest focal length of 24mm it has very strong barrel distortion that Imatest measured at -3.70%, which then immediately switches to pincushion distortion at around the 35mm mark and continues to stay that way until 85mm. The amount of distortion is least visible at the 35mm mark, where we see about 2.07% pincushion distortion. Again, this sort of optical behavior is expected from a low cost zoom lens, so no real surprises here. In fact, even the Nikon 24-120mm VR shows similarly pronounced distortion throughout its focal length range. While distortion issues can be easily fixed in post-processing software like Lightroom and Photoshop, strong levels of distortion mean that some of the image will have to be cropped after the image is adjusted for distortion.
11) Chromatic Aberration
All chromatic aberration tests were performed using RAW images (CA correction turned off both in camera and in post-processing). The Nikon 24-85mm VR exhibits pronounced lateral chromatic aberration at the shortest focal length of 24mm, with CA levels reaching close to 4 pixels in the extreme corners. As the focal length and aperture increase, CA levels drop to somewhat acceptable numbers. Here are some results from Imatest:
When it comes to Longitudinal Chromatic Aberration (LoCA), the Nikon 24-85mm VR seems to handle it quite well.
Let’s take a look at how the lens compares to other similar class lenses. Select the next page below.